Method of assembling a motor bearing and seal in a motor

ABSTRACT

A bearing and seal assembly for use in an electric motor rotor or stator bore about a central shaft. The bearing and seal assembly comprises a drawn aluminum sleeve dipsosed in and secured to the wall of the bore and having opposite end portions projecting beyond the bore wall. A sleeve bearing is press fit in the sleeve with the sleeve press fit or adhesively secured in the bore. An annular seal is press fit in one projecting end portion of the sleeve and is thus held in precise coaxial relationship with the bearing. The opposite projecting end portion of the sleeve provides a seat for an O-ring at a diametrically enlarged portion thereof. A cap in snap engagement with the rotor or stator, or alternatively with the sleeve, engages the O-ring and closes a lubricant chamber surrounding the bearing and within the sleeve. The assembly method includes press fitting of the bearing and seal in the sleeve with the elements mounted on an assembly pin for precise concentricity or coaxial relationship. Alternatively, the sleeve may be press fit in the rotor or stator bore or adhesively secured therein.

BACKGROUND OF THE INVENTION

This invention relates to small electric motors of the type used inaxial flow air impeller units commonly found in computers, copy machinesetc. More particularly, the invention relates to an improved bearing andseal assembly for use about a central shaft and within a stator or rotorof such a motor. The bearing and seal assembly in a motor of this typemust be of a relatively simple and inexpensive construction and yethighly efficient and dependable in use throughout the substantial lifespan of the unit.

In U.S. Pat. No. 3,614,261 entitled BEARING SEAL MEANS FOR ANELECTRICALLY DRIVEN FAN issued Oct. 19, 1971 to Karl E. Friese et al, abearing and seal assembly is disclosed with a sleeve bearing disposedwithin a ferrule or sleeve which provides a capillary sealing functionat one end and which is enlarged and closed at an opposite end toprovide a lubricant chamber about the bearing. The ferrule or sleeve is,however, of relatively heavy and expensive construction and thecapillary sealing function is provided by a cup-shaped projecting endportion of the sleeve and an associated annular felt ring. Closetolerances and precise concentricity or coaxial relationship between thesleeve bearing and the portion of the sleeve providing the capillaryseal are of course desired but have been found somewhat difficult toachieve and the construction has also been found deficient in thisregard.

It is the general object of the present invention to provide a bearingand seal assembly which includes a bearing and seal confining sleeve andwhich provides for the necessary close tolerances, precise concentricityor coaxial relationship of elements, and which is yet of a desirablysimple and inexpensive construction yielding a high degree of efficiencyand dependability in use.

A further object of the invention resides in the provision of anassembly method whereby the sleeve receives the bearing and seal inpress fit engagement and precisely centers the elements about anassembly pin with the sleeve press fit or adhesively secured within thebore of a motor stator or rotor.

SUMMARY OF THE INVENTION

In fulfillment of the foregoing objects and in accordance with thepresent invention, a soft deformable and smooth thin walled sleeve isprovided and is preferably of drawn aluminum. Press fitting of a sleevebearing and an annular seal while mounted on an assembly pin is readilyaccomodated by the smooth walled and deformable sleeve and the elementsare precisely centered and located by the assembly pin. The sleeve maybe simultaneously urged into press fit engagement with the wall of thebore in a stator or rotor or, alternatively, the sleeve may beadhesively secured in the bore. The desired precise concentricity orcoaxial relationship of elements is thus readily achieved in a simpleand inexpensive assembly procedure and efficient and long service liferesults.

In final assembly the thin walled sleeve resides in the bore of theannular element comprising a stator or rotor with one end portionthereof peripherally unrestrained e.g. projecting beyond the wall of thebore and confining the annular seal. The seal has an internal diameterin close tolerance relationship with an associated shaft to provide thedesired capillary action and lubricant grooves are provided between theseal and the adjacent sleeve bearing. The bearing also preferablyincludes axial lubricant grooves along its peripheral surface and anopposite end portion of the sleeve of enlarged diameter seats an O-ringwhich engages an annular flange on a closure member or cap whereby todefine a lubricant chamber about the bearing and within the sleeve.Thus, the sleeve provides for the necessary close tolerance relationshipbetween bearing and shaft and seal and shaft and for preciseconcentricity or coaxial relationship between bearing and seal and alsoprovides an oil or lubricant chamber about the bearing and an associatedportion of a central shaft within the bearing.

In practicing the assembly method of the invention, the sleeve bearingand annular seal are arranged in end-to-end relationship on an assemblypin which has precisely coaxial adjacent diameters substantially equalrespectively to the desired final internal diameters of the bearing andthe seal. A drawn aluminum or otherwise soft deformable and smooth thinwalled sleeve is provided with an external diameter slightly smallerthan the bore in a major annular motor element which may be a stator orrotor. The internal diameter of the thin walled sleeve is slightlysmaller than the external diameter of the sleeve bearing and the seal.The assembly pin with the bearing and seal thereon, the sleeve, and theannular motor element are axially aligned for precise coaxial movementof the pin relative to the bore in the annular element. When the sleeveis to be secured within the bore by a press fit engagement, the sleeveis first disposed in the bore, and the bearing and seal are then urgedaxially into the sleeve. Alternatively, when the sleeve is to be securedin the bore adhesively, the sleeve is aligned axially as described butis positioned externally of the bore for press fitting of the bearingand seal therewithin. The assembled sleeve, bearing, and seal are thenmoved axially into the bore for adhesive retention therein. In eitherevent, the sleeve readily accomodates press fitting of the bearing andseal therewithin while the assembly pin provides for the preciselocation of the bearing and seal thereon.

When the sleeve is disposed in the bore of the annular element so as tobe simultaneously press fit therein during the press fitting operationof the bearing and seal within the sleeve, the sleeve bearing ispreferably compressed during axial movement into the sleeve and a slightreduction of its internal diameter occurs about the assembly pin. Thus,the sleeve bearing is precisely sized about the pin during the pressfitting operation. The annular seal is press fit within a projecting endportion of the sleeve beyond the wall of the bore of the annular elementand is retained in precise concentricity or coaxial relationship withthe bearing with the free end portion of the sleeve expanding orotherwise deforming as required to accomodate any non-concentricityencountered. Thus, the assembly pin remains in dimensional control atall times and the precise concentricity or coaxial relationship ofbearing and seal is readily assured.

Press fitting of the sleeve in the bore of the annular element isprovided for by slightly oversizing the external diameter of the bearingand secure retention of the assembly within the bore is achieved.Irregularities in the bore wall, which may derive from a laminatedconstruction of the annular element, serve to further enhance retentionof the sleeve in the bore. During press fitting of the bearing and sealwithin the sleeve and resulting press fitting of the sleeve, the softdeformable material of the sleeve at least partially enters depressionsin the bore wall and the sleeve is thus positively secured against axialmovement relative to the bore wall.

When the sleeve is adhesively secured in the bore of the annularelement, the through openings in the sleeve bearing and the annular sealare precisely dimensioned or sized during manufacture and suchdimensions are retained with the elements mounted on the assembly pinduring press fitting within the sleeve. Expansion or other deformationof the sleeve accomodates any non-concentricity and preciseconcentricity or coaxial relationship of the elements is maintained. Onentry of the assembled sleeve, bearing and seal into the bore with theassembly pin within the bearing and seal, the previously establishedconditions are further maintained for the desired final relationship ofthe elements of the assembly. Adhesive retention of the assembly in thebore may be provided for by a preceeding application of adhesive to theexternal surface of the sleeve.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of an electric motor driven axial flow airimpeller with a motor which includes the improved bearing and sealassembly of the present invention,

FIG. 2 is an enlarged fragmentary vertical section through the motortaken generally as indicated at 2,2 in FIG. 1 and illustrating theimproved bearing and seal assembly,

FIG. 3 is a further enlarged fragmentary section showing a portion of abore adjacent rotor laminations and a portion of an adjacent sleeve andbearing forming a part of the bearing and seal assembly,

FIG. 4 is an elevational view of an alternative end cap for a lubricantchamber within the motor,

FIG. 5 is a fragmentary section through the end cap of FIG. 4 asindicated generally at 5,5 and through an end portion of the electricmotor, the end cap being illustrated in an exploded and disassembledposition,

FIG. 6 is a somewhat schematic vertical section through a rotor of theelectric motor, a sleeve, bearing, seal, and gasket of the bearingassembly, the various elements being illustrated in an initial positionof assembly with the bearing, seal, and gasket mounted on an assemblypin,

FIG. 7 is a somewhat schematic view similar to FIG. 6 but showing thevarious elements of the bearing and seal assembly in an assembledarrangement within the bore of the rotor,

FIG. 8 is a further somewhat schematic view similar to FIGS. 6 and 7 butshowing the assembly pin in a position of withdrawal and a ram member ina position of withdrawal,

FIG. 9 is a somewhat schematic sectional view illustrating analternative method of assembly with the various parts in preliminary andunassembled positions,

FIG. 10 is a somewhat schematic sectional view similar to FIG. 9 butshowing the various parts of the bearing and seal assembly in assembledpositions within the bore of the rotor of an electric motor.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring particularly to FIGS. 1 and 2, it will be observed that asmall electric motor driven axial flow air impeller, indicated generallyat 10, has a generally rectangular housing 12 which defines an axial airpassageway 14 and which includes a central housing portion 16 supportedby circumaxially spaced radial struts 18,18. The central housing portion16 contains the small electric motor which drives a plurality of fanblades 20,20 for impelling an axial flow of air through the passageway14. As best illustrated in FIG. 2, the electric motor has a rotor,indicated generally at 22, which is connected in driving relationshipwith a cup-shaped member 24, partially shown, and which at its peripherycarries the air moving blades 20,20. The rotor 22 may be connected withthe cup-shaped member 24 at a central circular opening 26 in the memberas by peening or staking of a rotor flange at 28.

At a left-hand portion of FIG. 2, the inner or central housing portion16 mounts a motor shaft 30 in cantilever fashion, the shaft extendingrightwardly in FIG. 2 and having an associated bearing and seal assemblyindicated generally at 32. The bearing and seal assembly 32 embodies thepresent invention.

The shaft 30 is stationary as disclosed in FIG. 2 with the bearing andseal assembly 32 and the rotor 22 rotatable thereabout. It will beapparent, however, that relative rotation is the essence and that arotating shaft and a stationary bearing and seal assembly within astator falls within the scope of the present invention. Thus, theimproved bearing and seal assembly of the invention is usable with amajor annular element of an electric motor or the like whether theannular element comprises a rotor, a stator, or other motor element.

Whether stationary or rotary, the annular element 22 is provided with acentrally located through bore 34 and the improved bearing and sealassembly of the present invention is fixedly mounted therein. Inaccordance with the invention, a soft deformable and smooth thin walledsleeve is disposed in and secured to the wall of the bore such as 34. Asshown, such a sleeve is illustrated at 36 in FIG. 2 and is of drawnaluminum, manufactured for example by eyelet machine or the eyeletprocess, and has a smooth surfaced thin side wall well suited to thepress fitting operations of the present invention. The aluminum used inthe construction of the sleeve 36 is identified by the AluminumAssociation as number 3005 Aluminum and, as an illustrative example, thethickness of the wall of the sleeve is 0.0135 to 0.0145 inches. Theinternal diameter of the sleeve 36 is nominally 0.463 inches prior toassembly in a press fit operation to be described hereinbelow.

The sleeve 36 has a left-hand projecting end portion 38 of slightlyreduced diameter and a radially inwardly projecting flange 40 isintegrally formed with the sleeve and has a central opening 42 in spacedrelationship with the shaft 30. The main or body portion of the sleeve36 resides within the bore 34 with the portion 38 projecting leftwardlyfrom the wall of the bore and with a right-hand end portion 44 of thesleeve projecting rightwardly from the wall of the bore 34. That is, theright-hand end portion 44 of the sleeve 36 is enlarged diametrically toprovide an annular seat at 46 for an O-ring 48. A radially outwardlyprojecting strengthening flange 50 is integrally formed at an extremeright-hand end portion of the sleeve 36 and may seat against a radialsurface on the rotor 22. Thus, a closure member or end cap may beprovided as at 52 for snap engagement in an end opening 54 in the rotor22 to engage the O-ring at an annular flanged portion 56 and to thusprovide an oil or lubricant chamber 58 within the sleeve 36.

The oil or lubricant chamber 58 is defined by the sleeve 36, O-ring 48,end cap 52, and a seal 60 disposed within the reduced diameter andleftwardly projecting end portion 38 of the sleeve. Thus, the chamber 58resides about a sleeve bearing 62 and a right-hand portion of the shaft30 and provides for the desired lubrication of the bearing and shaft.

The left-hand end of the oil or lubricant chamber 58 is defined byannular seal 60 as stated and by a small gasket 64 disposed between theseal 60 and the end flange 40 on the sleeve 36. That is, the spacebetween the annular seal 60 and the shaft 30 is so limited as to preventthe axial outward flow of oil or other lubricant leftwardly past theseal and, in the embodiment shown, the said space or clearance isnominally 0.004 inches. A capillary action is thus provided for and,rather than flowing leftwardly beyond the seal, oil or other lubricantis thrown radially outwardly between the seal 60 and the bearing 62 asprovided for by space 66. The space 66 may represent a plurality ofradial grooves in the end surface of the bearing 62 communicating withaxially extending grooves 68,68, one shown, along the periphery of thebearing. The gasket 64 prevents the leakage of oil or other lubricantleftwardly around the outer or peripheral surface of the annular seal60. The gasket may be of a soft conventional material and the end seal60 may be similarly constructed in a conventional manner as fromsintered iron.

The sleeve bearing 62 may also be conventional and may, for example, beof sintered bronze with substantial void or air space for the absorbtionof oil or other lubricant. Thus, the oil or other lubricant permeatesthe bearing 62 and provides for oil film rotational contact between theshaft 30 and bearing 62 within the oil or lubricant chamber 58, theenlarged right-hand end portion of the chamber serving as an oil orlubricant sump.

At its right-hand end portion, the shaft 30 carries a washer 70, O-ring72, and snap ring 74, all in a conventional manner. Annular felt membersmay be provided at 76 and a conventional thrust element 78 engages anarcuate end portion of the shaft 30.

In FIGS. 4 and 5, an alternative end cap arrangement is illustrated andmay include an end cap 52a having a plurality of axial openings 80,80,three shown, each with a small seat 82, formed therein. The openings80,80 are adapted to respectively receive a plurality of small hookmembers 84,84, one shown, formed integrally on and projectingrightwardly from the sleeve 36. With the cap 52a moved leftwardly asindicated by phantom line in FIG. 5 and entered in rotor opening 54a,the small hook members 84,84 flex inwardly and thereafter engage theseats 82,82 whereby to secure the cap in its assembled position. Annularflange 56a on the cap engages O-ring 48a in sealing relationship as inthe case of the flange 56 and O-ring 48 in FIG. 2.

As is well known, the efficiency and long life of a lubrication systemsuch as described is dependent upon the maintenance of close tolerancesand dimensional relationships between shaft and bearing and shaft andseal and upon precise concentricity or precise coaxial relationshipbetween a bearing and its associated seal. The establishment andmaintenance of the desired conditions is greatly facilitated in thepresent invention with the use of the specific drawn aluminum sleeve 36and with the assembly method of the invention involving the mounting ofthe bearing and seal on an assembly pin and the subsequent press fittingof the bearing and seal within the sleeve.

A first form of the method of the invention is illustrated in FIGS. 6-8and involves the step of aligning the bearing, seal, shell, and rotor orother annular element with the bearing and seal mounted on an assemblypin such as illustrated at 86. In FIGS. 6-8 the rotor or other annularelement 22 is supported by a base member 88 and loosely positioned by anannular member 90 with sleeve 36 loosely entered in the bore 34 of theannular member. Thus, the sleeve 36 has an external diameter slightlysmaller than the internal diameter of the bore 34 and the internaldiameter of the sleeve 36 is slightly smaller than the external diameterof the sleeve bearing 62. In the FIGS. 6-8 embodiment of the method, andwhen a press fit of the sleeve 36 in the bore 34 is desired, a 0.494inch diameter bore may be provided with a sleeve dimensioned as above.That is, a sleeve having a nominal 0.014 inch wall thickness and a 0.463internal diameter may be employed in the illustrative example. A bearinghaving a nominal external diameter of 0.470 inches may be mounted on theassembly pin 86 as illustrated. Thus, if the sleeve 36 were allowed tofreely expand with the bearing 62 entered therewithin, the sleeveinternal diameter would increase to 0.470 inches and its externaldiameter would increase to 0.470 plus 0.028 (twice wall thickness) or to0.498 inches. With a 0.494 inch bore a 0.004 press fit will thus beprovided. That is, the sleeve will be urged into press fit engagementwith the bore 34 by the axial entry of the bearing 62 within the sleeve.

As stated, the assembly pin 86 controls the internal diameters of thebearing 62 and the seal 60. As illustrated, the gasket 64 is disposedabout the pin and may be readily urged downwardly for engagement withthe end flange 42 on the sleeve 36. The seal 60 is mounted on the pinand rests upon a small shoulder 92 and resides about a pin portion 94 ofpredetermined diameter. The diameter of the portion 94 is slightlysmaller than the internal diameter of the seal 60 but only as requiredto permit the subsequent withdrawal of the pin from within the seal,FIG. 8, said diameter being predetermined to provide a relatively tightfit of the seal thereabout and to thus establish and maintain thedesired concentricity of the seal 60 and bearing 62.

The external diameter of the seal 60 is shown in FIG. 6 as beingsomewhat less than that of the bearing 62 so as to provide for the freedownward passage of the seal 60 within the sleeve 36 to the reduceddiameter portion 38 thereof. On reaching the reduced diameter portion38, the seal 60 is engaged therewith in a press fit by the downwardurging of the bearing 62, in turn urged downwardly by ram member 96 inFIG. 7. As will be apparent, the reduced diameter portion 38 of thesleeve lacks external constraint and is free to expand uniformly orotherwise deform as required to accomodate non-concentricities and topermit the pin 86 to establish the required precise concentricity of theinternal opening of the seal 60 with the internal opening in the bearing62.

The diameter of the portion 98 of the assembly pin 86 residing withinthe bearing 62 in FIG. 6 is preferably slightly larger than the desiredfinal internal diameter of the bearing 62. That is, the bearing 62,formed of sintered bronze or the like, is relatively soft and deformableso as to be compressed as it is urged downwardly within the confinedportion of the sleeve 36. The internal diameter of the bearing 62 maythus be reduced slightly with the wall of the central opening in thebearing tightly engaging the pin portion 98 so as to be dimensioned orsized thereby. When the pin 86 is withdrawn downwardly as in FIG. 8, thewall of the internal opening in the bearing 62 may expand slightlyinwardly and this can be provided for in proper sizing of the pin. Inthe illustrative example above, the bearing 62 with a 0.470 inchexternal diameter is provided with an initial internal diameter in therange 0.1878 to 0.1882 inches. The desired final dimension of theinternal opening in the bearing 62 is in the diameter range between0.1875 and 0.1877 inches. The inward expansion of the wall of thebearing opening or internal diameter reduction on withdrawal of the pin86 is found to be approximately 0.0002 inches. Accordingly, thedimension of the pin portion 98 should be a diameter in the range 0.1877to 0.1878 inches.

In the foregoing example, dimensioning or sizing of the bearing internaldiameter is precisely controlled by the pin 86 and with preciseconcentricity or coaxial relationship of the pin portions 94 and 98, theresulting bearing assembly as in FIG. 8 exhibits a corresponding precisedimensional relationship and precise concentricity of bearing and seal.The FIG. 7 and 8 steps of the method will be apparent from the schematicillustration thereof with the ram 96 descending and urging the seal andbearing into press fit engagement with the sleeve. The bearingsimultaneously urges the sleeve into press fit engagement with the wallof the bore in the annular element, and is simultaneously sized at itsinternal diameter as required, precise concentricity being maintainedthroughout. The ram 96 and pin 86 are thereafter withdrawn in oppositedirections as illustrated in FIG. 8 and the assembly procedure iscomplete.

A further feature of the press fit engagement of the sleeve 36 withinthe bore 34 of the annular member 22 is illustrated in FIG. 3. The wallof the bore 34 may have significant irregularities as for example in thecase of a rotor of laminated construction. Thus, small depressions inthe wall may exist as at 100, 100 in FIG. 3. When the soft deformablesleeve 36 is urged outwardly by the press fit of the bearing 62therewithin the periphery of the sleeve is slightly expanded into orperipherally conforms with the depressions whereby to secure the sleeveagainst axial movement relative to the bore wall. This condition iseffective on final assembly to prevent relative sleeve movement and, itshould be noted, is also effective during the press fitting operation.That is, as the bearing is entered within the sleeve, FIGS. 6, 7, theperipheral surface of the sleeve grips the depressions betweenlaminations in the rotor wall and the sleeve is thus held againstunintended or accidental downward dislodgement as might otherwise resultfrom the downward bearing movement therewithin. Such downwarddislodgement might result in deformation of the upwardly projectingportion of the sleeve 36 beyond the end of the bore wall 34. Forexample, with a deformable and relatively fragile sleeve, the O-ringseat at the upper portion of the sleeve might be otherwise flareddownwardly or deformed so as to result in an ineffective seatconfiguration.

In FIGS. 9 and 10, an alternative form of the assembly method isillustrated wherein the sleeve 36a is adhesively secured within bore 34aof annular member 22a. In this form of the method, the elementsincluding the annular member 22a, the sleeve 36a, the gasket 64a, seal60a, bearing 62a and assembly pin 86a are aligned axially as in theembodiment of the method described above. It will be noted, however,that the sleeve is positioned externally of the bore 34a and held by anannular shoulder 102 on a lower portion of the pin 86a. In this positionof the sleeve 36a, adhesive may be applied externally as indicated at104, and the gasket, seal, and bearing may be urged downwardly for pressfit engagement of the seal and bearing within the sleeve 36a. Ram 96aoperates with the pin 86a held in the FIG. 9 position and with the upperportion of the pin moving downwardly within the lower portion thereofwhich defines the annular seat 102. When the bearing, seal, and gaskethave been assembled within the sleeve 36a, continuing downward rammovement urges the assembled sleeve, bearing, seal, and gasket to theFIG. 10 position with the lower pin portion moving downwardly to theFIG. 10 position. On full withdrawal of the ram and pin, and on curingof the adhesive, the assembly is secured within the annular element 22aas required.

As will be apparent, the sleeve 36a is capable of free uniform expansionand other deformation in the FIG. 9 position. Thus, the assembly pincontrols concentricity of elements but does not serve as a dimensioningor sizing element for the internal diameter of the bearing 62a. Thebearing in this instance is provided with a precise internal diameter asrequired prior to assembly and bearing compression is avoided during theassembly operation. Precise concentricity or coaxial relationship of theelements is nevertheless established and maintained as required. Anynon-concentricity encountered is accomodated by expansion or deformationof the sleeve 36a as in the case of the FIG. 6-8 embodiment.

From the foregoing it will be apparent that an improved bearing and sealassembly and an associated assembly method have been provided. Theassembly method shows a high degree of ease and convenience and isconducive to manufacture at economic advantage. The resulting bearingand seal assembly is highly efficient and dependable in long servicelife.

We claim:
 1. In a method for assembling a sleeve bearing and a similar adjacent annular seal within the bore of and in fixed relationship to a major annular element of an electric motor or the like; the steps comprising axially aligning the sleeve bearing and the seal in end-to-end relationship on an assembly pin having precisely coaxial adjacent diameters substantially equal respectively to the desired final internal diameters of the bearing and seal, providing a soft deformable and smooth thin walled sleeve having an external diameter slightly smaller than the bore in the annular motor element and an internal diameter slightly smaller than the external diameter of the sleeve bearing and end seal, axially aligning the assembly pin and sleeve with the annular element for precise coaxial movement of the pin relative to the bore in the annular element, providing such relative movement and effecting a press fit of the bearing and seal in precise coaxial alignment within the sleeve with the sleeve secured in the bore of the annular element, the sleeve being at least partially deformed during such movement and the internal diameters of the bearing and seal respectively closely conforming to the adjacent coaxial external diameters of the pin and thus residing in precise coaxial relationship with each other in the sleeve, and axially withdrawing the assembly pin from within the bearing and seal.
 2. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 1 wherein the alignment step includes the step of positioning the sleeve within the bore of the annular element with the assembly pin, bearing, and seal arranged externally of but in alignment with the bore and sleeve, and wherein relative axial movement is effected between the pin with the bearing and seal thereon and the annular element with the sleeve therewithin, the press fit of the bearing and seal within the sleeve resulting therefrom.
 3. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 2 wherein the annular element is provided with a bore having an internal diameter somewhat less than the expanded external diameter of the sleeve with the bearing press fit therewithin, the press fit of the bearing within the sleeve with the latter confined by the bore wall thus resulting in a corresponding press fit of the sleeve within the bore.
 4. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 3 wherein the wall of the bore in the annular member has significant irregularities, and wherein the adjacent wall of the sleeve is deformed to at least partially enter depressions in the bore wall during press fitting of the bearing within the sleeve, the sleeve being thus secured positively in the bore.
 5. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 4 wherein said annular element is provided with a through bore, wherein the sleeve is dimensioned so as to have a seal receiving end portion projecting beyond the bore wall at one end, and wherein the seal and bearing are arranged on the assembly pin for sequential entry into the sleeve in the element bore so that the seal passes through the main portion of the sleeve and resides in said projecting end portion of the sleeve in its fully assembled position.
 6. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 5 wherein the sleeve is provided with a projecting end portion with a diameter somewhat smaller than the diameter of the main portion of the sleeve, and wherein the seal is provided with an external diameter somewhat smaller than that of the bearing for the free axial passage of the seal through said main portion of the sleeve to said projecting portion.
 7. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 6 wherein the internal diameter of the seal is slightly larger than the internal diameter of the bearing with the corresponding coaxial diameters of the assembly pin similarly dimensioned.
 8. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 3 wherein the sleeve bearing is of a soft deformable material and has an external diameter sufficiently larger than the internal diameter of the sleeve to provide for significant compression and internal diameter reduction of the bearing during axial entry and press fitting of the bearing in the sleeve, the internal diameter of the bearing thus being precisely established by and about the assembly pin during the press fit operation.
 9. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 8 wherein the initial diameter of the sleeve bearing is slightly greater than the desired final internal diameter thereof as established by the assembly pin.
 10. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 1 wherein the alignment step includes the alignment of the annular element, the sleeve, and the pin with the bearing and seal thereon, all externally of the bore of the annular element, the press fit of the bearing and seal in the sleeve being effected with the sleeve remaining externally of the bore, and the assembly comprising the sleeve with the bearing and seal press fit therein and retained on the assembly pin being axially entered in the bore in the annular element and secured in position therein.
 11. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 10 wherein the bearing external diameter is greater than the sleeve internal diameter but such that the sleeve subsequent to expansion by the bearing has an external diameter smaller than the bore for free axial entry of the assembly into the bore, and wherein the sleeve with the bearing and seal therewithin is adhesively secured in the bore.
 12. The method for assembling a sleeve bearing and annular seal in the bore of an annular element as set forth in claim 10 wherein said annular element has a through bore and the sleeve is dimensioned so as to have an end portion projecting beyond the bore wall at one end, and wherein the seal and bearing are arranged on the assembly pin for sequential entry into the sleeve so that the seal resides in said projecting end portion of the sleeve in the fully assembled position of the elements. 